Basically, slightly faster instruction executions due to improvements in the architecture; basically 3% - 5% every generation since the 2nd generation Sandy Bridge series. Slightly higher clockspeed which also helps performance. Slightly more power efficient. The biggest improvement though is generally the integrated graphics core; the Intel HD's performance increases by roughly 15% every generation. For example, the Intel HD 620 in 7th gen CPUs is roughly around 200% more powerful than the Intel HD 3000 in 2nd generation CPUs. If only CPU performance increases by that much...